A proof of concept application of aptachain: ligand-induced self-assembly of a DNA aptamer. Issue 3 (14th January 2019)

• Record Type: Journal Article
• Authors: Neves, Miguel A. D.; Slavkovic, Sladjana; Reinstein, Oren; Shoara, Aron A.; Johnson, Philip E.
• Is Part Of: RSC advances. Volume 9:Issue 3(2019)
• Page Start: 1690
• Page End: 1695
• Publication Date: 2019-01-14
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra07462c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : We present the concept of aptachain. An aptamer is split into two overlapping strands that form an oligomer when it binds its target. Aptachain formation can be used to detect ligand binding and may be beneficial in other biotechnology applications. Abstract : A challenge for the use of aptamers as biosensors is how to signal the occurrence of their ligand binding event into a signal that can be exploited in a detection scheme. Here, we present the concept of "aptachain" formation, where an aptamer is split into two overlapping or staggered strands and assembles into an extended oligomer upon ligand binding. This assembly of aptamers can then be used as a way to detect ligand binding by the aptamer. As an example of this concept, we employed the cocaine-binding aptamer as a model system, used its ability to tightly bind quinine and demonstrated its capability in a gold nanoparticle-based biosensing application. We used isothermal titration calorimetry to demonstrate that, when split into two overlapping DNA strands, the aptamer remains functional. Size-exclusion chromatography showed that the quinine-bound oligos form a larger assembly of aptamer units than in the absence of ligand. Finally, we used the oligomer forming ability of the aptachain oligos in a biosensor application for quinine that brings gold nanoparticles closer together resulting in a shift in their plasmonic resonance to a longer wavelength and an observed colour shift. We propose that splitting aptamers into overlapping strands that form oligomers in the presence of a ligand, aptachain formation, will be generally applicable to aptamers and prove useful in a variety of biotechnology applications.